CVE-2026-55698

pnpm is a package manager. Prior to 10.34.2 and 11.5.3, pnpm can persist package-manager bootstrap metadata in the first YAML document of pnpm-lock.yaml. Before the patch, direct pnpm execution trusted an already resolved packageManagerDependencies entry when the committed env lockfile contained matching pnpm and @pnpm/exe versions. A malicious repository could therefore commit package-manager lockfile package records and snapshots that bypassed fresh package-manager resolution, then cause pnpm to install and execute bytes selected by that committed lockfile state during automatic version switching. This vulnerability is fixed in 10.34.2 and 11.5.3.

pnpm is a package manager. Prior to 10.34.2 and 11.5.3, pnpm can persist package-manager bootstrap metadata in the first YAML document of pnpm-lock.yaml. Before the patch, direct pnpm execution trusted an already resolved packageManagerDependencies entry when the committed env lockfile contained matching pnpm and @pnpm/exe versions. A malicious repository could therefore commit package-manager lockfile package records and snapshots that bypassed fresh package-manager resolution, then cause pnpm to install and execute bytes selected by that committed lockfile state during automatic version switching. This vulnerability is fixed in 10.34.2 and 11.5.3.

<!-- maintainer-action:start -->

Maintainer Action Plan

This report is ready to review with the shared patch branch. Start with the PR and the expected fixed behavior, then use the detailed exploit narrative below only if you want to replay the original path.

• Advisory: CAND-PNPM-063 / GHSA-w466-c33r-3gjp
• Advisory URL: https://github.com/pnpm/pnpm/security/advisories/GHSA-w466-c33r-3gjp
• Shared patch PR: https://github.com/pnpm/pnpm-ghsa-j2hc-m6cf-6jm8/pull/1
• Shared patch branch: security/ghsa-batch-2026-06-09
• Patch commit: a93449314f398cf4bdf2e28d033c02d37395ad22
• Base commit: origin/main 55a4035abf1ae3fe7208ba1f5ef43c5eff58ccec
• Maintainer priority: start-here
• Component: pnpm packageManager env lockfile
• Patch area: package-manager env lockfile is re-resolved through trusted registries before execution
• Affected packages: npm:pnpm, npm:@pnpm/installing.env-installer
• CWE IDs: CWE-829, CWE-494, CWE-345
• Conservative CVSS: 8.8 / CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
• Next action: review the shared patch branch for this component, set the final affected version range, merge and release the fix, then publish or close the advisory.

Expected Patched Behavior

Committed env-lockfile package-manager entries are force-refreshed through trusted registries before execution; attacker tarball requests and markers stay at zero.

Files And Tests To Review

• installing/env-installer/src/resolvePackageManagerIntegrities.ts
• pnpm/src/switchCliVersion.ts
• pnpm/src/switchCliVersion.test.ts
• .changeset/clean-package-manager-registries.md

Focused Validation

Run these from a checkout of the shared patch branch. They are the useful maintainer commands with machine-local artifact paths removed.

./node_modules/.bin/tsgo --build installing/env-installer/tsconfig.json
./node_modules/.bin/tsgo --build pnpm/tsconfig.json
PNPM_REGISTRY_MOCK_PORT=7799 NODE_OPTIONS="--experimental-vm-modules --disable-warning=ExperimentalWarning --disable-warning=DEP0169" ../node_modules/.bin/jest src/switchCliVersion.test.ts -t "re-resolved package-manager lockfile" --runInBand
PNPM_REGISTRY_MOCK_PORT=7799 NODE_OPTIONS="--experimental-vm-modules --disable-warning=ExperimentalWarning --disable-warning=DEP0169" ../node_modules/.bin/jest src/switchCliVersion.test.ts src/syncEnvLockfile.test.ts --runInBand
./node_modules/.bin/eslint installing/env-installer/src/resolvePackageManagerIntegrities.ts pnpm/src/switchCliVersion.ts pnpm/src/switchCliVersion.test.ts
git diff --check

The full patched replay for the shared branch passed with all 20 candidates marked fixed. This candidate's replay evidence is results/CAND-PNPM-063-patched-result.json.

<!-- maintainer-action:end -->

Summary

pnpm can persist package-manager bootstrap metadata in the first YAML document of pnpm-lock.yaml. Before the patch, direct pnpm execution trusted an already resolved packageManagerDependencies entry when the committed env lockfile contained matching pnpm and @pnpm/exe versions. A malicious repository could therefore commit package-manager lockfile package records and snapshots that bypassed fresh package-manager resolution, then cause pnpm to install and execute bytes selected by that committed lockfile state during automatic version switching.

Details

The vulnerable source-to-sink path was:

• lockfile/fs/src/envLockfile.ts reads the repository's first YAML lockfile document and validates shape only.
• pnpm/src/main.ts reaches switchCliVersion() when a direct pnpm invocation sees a wanted pnpm package manager with onFail=download.
• pnpm/src/switchCliVersion.ts reads the committed env lockfile when package-manager metadata should be persisted.
• installing/env-installer/src/resolvePackageManagerIntegrities.ts treated packageManagerDependencies as resolved when only the pnpm and @pnpm/exe versions matched.
• engine/pm/commands/src/self-updater/installPnpm.ts…

pnpm is a package manager. Prior to 10.34.2 and 11.5.3, pnpm can persist package-manager bootstrap metadata in the first YAML document of pnpm-lock.yaml. Before the patch, direct pnpm execution trusted an already resolved packageManagerDependencies entry when the committed env lockfile contained matching pnpm and @pnpm/exe versions. A malicious repository could therefore commit package-manager lockfile package records and snapshots that bypassed fresh package-manager resolution, then cause pnpm to install and execute bytes selected by that committed lockfile state during automatic version switching. This vulnerability is fixed in 10.34.2 and 11.5.3.

pnpm is a package manager. Prior to 10.34.2 and 11.5.3, pnpm can persist package-manager bootstrap metadata in the first YAML document of pnpm-lock.yaml. Before the patch, direct pnpm execution trusted an already resolved packageManagerDependencies entry when the committed env lockfile contained matching pnpm and @pnpm/exe versions. A malicious repository could therefore commit package-manager lockfile package records and snapshots that bypassed fresh package-manager resolution, then cause pnpm to install and execute bytes selected by that committed lockfile state during automatic version switching. This vulnerability is fixed in 10.34.2 and 11.5.3.

<!-- maintainer-action:start -->

Maintainer Action Plan

This report is ready to review with the shared patch branch. Start with the PR and the expected fixed behavior, then use the detailed exploit narrative below only if you want to replay the original path.

• Advisory: CAND-PNPM-063 / GHSA-w466-c33r-3gjp
• Advisory URL: https://github.com/pnpm/pnpm/security/advisories/GHSA-w466-c33r-3gjp
• Shared patch PR: https://github.com/pnpm/pnpm-ghsa-j2hc-m6cf-6jm8/pull/1
• Shared patch branch: security/ghsa-batch-2026-06-09
• Patch commit: a93449314f398cf4bdf2e28d033c02d37395ad22
• Base commit: origin/main 55a4035abf1ae3fe7208ba1f5ef43c5eff58ccec
• Maintainer priority: start-here
• Component: pnpm packageManager env lockfile
• Patch area: package-manager env lockfile is re-resolved through trusted registries before execution
• Affected packages: npm:pnpm, npm:@pnpm/installing.env-installer
• CWE IDs: CWE-829, CWE-494, CWE-345
• Conservative CVSS: 8.8 / CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
• Next action: review the shared patch branch for this component, set the final affected version range, merge and release the fix, then publish or close the advisory.

Expected Patched Behavior

Committed env-lockfile package-manager entries are force-refreshed through trusted registries before execution; attacker tarball requests and markers stay at zero.

Files And Tests To Review

• installing/env-installer/src/resolvePackageManagerIntegrities.ts
• pnpm/src/switchCliVersion.ts
• pnpm/src/switchCliVersion.test.ts
• .changeset/clean-package-manager-registries.md

Focused Validation

Run these from a checkout of the shared patch branch. They are the useful maintainer commands with machine-local artifact paths removed.

./node_modules/.bin/tsgo --build installing/env-installer/tsconfig.json
./node_modules/.bin/tsgo --build pnpm/tsconfig.json
PNPM_REGISTRY_MOCK_PORT=7799 NODE_OPTIONS="--experimental-vm-modules --disable-warning=ExperimentalWarning --disable-warning=DEP0169" ../node_modules/.bin/jest src/switchCliVersion.test.ts -t "re-resolved package-manager lockfile" --runInBand
PNPM_REGISTRY_MOCK_PORT=7799 NODE_OPTIONS="--experimental-vm-modules --disable-warning=ExperimentalWarning --disable-warning=DEP0169" ../node_modules/.bin/jest src/switchCliVersion.test.ts src/syncEnvLockfile.test.ts --runInBand
./node_modules/.bin/eslint installing/env-installer/src/resolvePackageManagerIntegrities.ts pnpm/src/switchCliVersion.ts pnpm/src/switchCliVersion.test.ts
git diff --check

The full patched replay for the shared branch passed with all 20 candidates marked fixed. This candidate's replay evidence is results/CAND-PNPM-063-patched-result.json.

<!-- maintainer-action:end -->

Summary

pnpm can persist package-manager bootstrap metadata in the first YAML document of pnpm-lock.yaml. Before the patch, direct pnpm execution trusted an already resolved packageManagerDependencies entry when the committed env lockfile contained matching pnpm and @pnpm/exe versions. A malicious repository could therefore commit package-manager lockfile package records and snapshots that bypassed fresh package-manager resolution, then cause pnpm to install and execute bytes selected by that committed lockfile state during automatic version switching.

Details

The vulnerable source-to-sink path was:

• lockfile/fs/src/envLockfile.ts reads the repository's first YAML lockfile document and validates shape only.
• pnpm/src/main.ts reaches switchCliVersion() when a direct pnpm invocation sees a wanted pnpm package manager with onFail=download.
• pnpm/src/switchCliVersion.ts reads the committed env lockfile when package-manager metadata should be persisted.
• installing/env-installer/src/resolvePackageManagerIntegrities.ts treated packageManagerDependencies as resolved when only the pnpm and @pnpm/exe versions matched.
• engine/pm/commands/src/self-updater/installPnpm.ts…

Root has patched CVE-2026-55698 in the @rootio/pnpm package for Root:npm. Multiple fixed versions available.